如果返回的 undefined 被覆盖,该插件会将 undefined
转译成 void 0
。
输入
foo === undefined;
输出
foo === void 0;
npm install babel-plugin-transform-undefined-to-void
.babelrc
(推荐).babelrc
{
"plugins": ["transform-undefined-to-void"]
}
babel --plugins transform-undefined-to-void script.js
require("babel-core").transform("code", {
plugins: ["transform-undefined-to-void"]
});